IDENTIFICATION AND ANTIBIOGRAM PROFILING OF ESCHERICHIA COLI AND SALMONELLA SPP. ISOLATED FROM SUPPLIED WATER OF SELECTED CATTLE FARMS IN DHAKA

Abstract

The present study was carried out to isolate, identify and to know antibiogram profiling of Escherichia coli and Salmonella spp. from the supplied drinking water in different cattle farms in Dhaka city within the period of October, 2020 to April, 2021. A total of 100 fresh water samples were randomly collected from different cattle farms and transported to the Microbiology and Parasitology laboratory of Sher-e-Bangla Agricultural University for microbiological analysis. Primary culture was done in nutrient broth and nutrient agar. Pure culture was obtained from different selective media. Bacteria were identified by observing the growth properties in different media, staining properties and biochemical tests. The characteristics of E. coli colonies were red to bright pink colored in MacConkey agar and greenish red colored with faint metallic sheen in EMB (Eosin Methylene Blue) agar. The characteristics of Salmonella spp. colonies were black colored in SS agar and pink colored in MacConkey agar. In Gram’s staining, E. coli revealed gram-negative, pink color, small rod-shaped appearance, arranged in single or paired short, and Salmonella spp. revealed gram negative, short rod shaped, singly arranged. The occurrence of E. coli was 46% and Salmonella spp. was 37%. Pure isolates were subjected to antibiogram by disc diffusion method against 5 different antibiotics including streptomycin (Str), ampicillin (Amp), ciprofloxacin (Cip), gentamycin (Gen) and tetracycline (Te). Highest number of E. coli isolates showed resistance to gentamycin (43%) followed by ampicillin (38%) and tetracycline (26%). In case of Salmonella spp., highest number of E. coli isolates showed resistance to gentamycin (31%) followed by ampicillin (31%) and tetracycline (27%). This study revealed that water samples collected from different cattle farms of Dhaka city were contaminated with multiple species of multidrug resistant bacteria which may pose risk for both animal and human health.